Hello Sarah,
Thank you for posting this question in the community forum.
I need to know which Update Roll up your CRM is on right now. I have tested this in my test lab and tried to edit a system view but do not get an option to add Products to an existing system view.
So the best view is to create a personal view wherein you would get an option to add the Product's Column to an Opportunity view.
Please let me know if this is what you were looking for.
Thank You.
Rob Moses